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troubles with Areca 1882x and RAID array
There seems to be a lot of knowledgeable people here so I wondered if somebody could help me figure out if I’m getting the best out of my RAID array. My setup is as follows…
Mac Pro 12 core (48 GB RAM / SSD Boot drive / Mountain Lion)
Areca 1882x SAS Card ( X8 lane )
Two SAS cables running to an Enhance-Tech E800MS 8 Bay Array fitted with 8 Hitachi 7K3000 (3TB) drives
I have a single RAID 6 volume setup (18 of 24TB usable).The issue I’m having is that although my write speeds are averaging around 950MB/s my read speeds are a lot slower, averaging around 300 MB/s for a large file. The biggest issue is that although write speeds kick in at full tilt immediately the read speeds build very slowly, starting at around 150 MB/s for a second or so then jumping up in steps over 4 – 5 seconds rather than smoothly and quickly.
One thing I’ve noticed is that if I disable the volume read ahead settings then speeds built slightly faster and settle around 3 seconds in with a large file.
There’s a lot of options for the card, and I’ve experimented with pretty much everything without increasing the read performance at all. Many options will degrade it further but the default settings seem to work best, other than the volume read ahead as stated.
Should I be seeing better read performance? From everything I’ve seen I expected reads and writes to be a lot closer. If there’s something I should be looking out for then any tips would be very much appreciated.
Regards
Paul.
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32 Replies
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Paul,
That card is not yet compatible with Mountain Lion. I would check with Areca to see when support will be available for it.
Jonathan Schilling
Vertical Sales Manager
Proavio
12221 Florence Ave.
Santa Fe Springs, CA 90670
Dir: 562-777-3498
Main: 562-777-3488 X106
Fax: 562-777-3499
Email: jon@proavio.comSee our forum: https://forums.creativecow.net/proavio
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Hi Jonathan.
According to the Areca website mountain lion includes drivers for their cards and it was certainly recognised without me having to installing anything so it seems that’s true. Of course, that doesn’t mean to say that the drivers are not to blame!
https://www.areca.com.tw/news/2012/n0726_2012.html
Other than the slow build up of read speeds it seems to be reliable and working well. I’ll see if I can move it over to another machine with Lion to compare the read performance.
Many thanks
Paul.
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This is strange, usually writes are slower – especially with RAID6.
Areca has decent support – tried contacting them?
Have you tried benching individual drives? Sometimes a single rogue drive brings down the array’s performance – sometimes in unusual ways.
Alex Gerulaitis
Systems Integrator
DV411 – Los Angeles, CA -
Hi Jon!
I’m using a ProAvio 800MS with Areca 1882x in a Sonnet Echo Express on Mountain Lion with no problem. In fact, it’s feeding out to 4 rooms over ethernet using a Small Tree 6 port ethernet card. If any system should be kicking up errors, it’s mine!
Life on the bleeding edge….
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Yes I’ve sent them an email, no response as yet.
How would you go about testing the individual drive performance when they are part of a RAID in an enclosure?
Thanks
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[Paul Joy] “How would you go about testing the individual drive performance when they are part of a RAID in an enclosure?”
Non-destructively (read-only), on a different system. In my shop, I have a system with 3 different types of eSATA ports and an eSATA dock. Plug the drive in, test it with HD_Speed (allows to bench a physical drive vs. a drive letter).
Another HD_Speed’s nifty feature (that neither WinSAT disk not BMD Disk Speed can do) is the ability to dial in the offset, e.g. “test at 99% capacity” which shows how the speed decreases towards the end of the drive.
Alex Gerulaitis
Systems Integrator
DV411 – Los Angeles, CA -
Hi Paul –
the Areca 1882x card has the driver native in the MAC OS X 10.8 operating system. It is driver 1.3.5. If you download the Areca stuff from https://www.areca.com.tw, and don’t UNCHECK the driver, when you want to intall MRAID, you will overwrite the 1.3.5 driver, and install the older 1.3.4 driver which is for Lion. The OS X 10.8 V1.3.5 driver is NOT on the Areca website, and I have no idea of how you get it back if you accidently overwrite it with V1.3.4 from the Areca website, other than to reinstall 10.8.You do not need TWO cables with the Areca 1882x and a modern 6g chassis – you only need one cable. I have recently seen a ProAvio sheet on tuning the Areca 1882x. They should post the link for this on this forum.
If you have continued troubles, you can email me at maxavid@cfl.rr.com
Bob Zelin
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Hi Bob, thanks.
I thought that might be the case when installing the software so I only ticked the arcHttp and CLI installers, the original driver that came with ML is still in use.
I was told by the supplier that each cable controls four drives in the enclosure, is that not normally the case?
Regards
Paul
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different chassis have different configurations. You must contact the manufacturer of the drive chassis to ask them how to hook it up. Most NEW (2010 – present) RAID chassis only use a single cable to a host adaptor card. The early chassis, that worked with products like the Areca 1221x required both cables. You can find out very quickly, by just hooking up one cable, and see how many drives show up in the MRAID utility. But call the company that makes the chassis – do not rely on these forums for your information.
Bob Zelin
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Enclosures with MiniSAS connectivity and without a SAS expander built in, require a standard 4-lane MiniSAS connector for each 4 drives. So two cables are required for your Enhance 8-bay E800MS box as long as you have more than 4 drives in it.
Enclosures with a SAS expander built-in (most of the boxes with more than 8 bays; some 8-bay boxes) require only one cable.
(On a side note: some advanced expanders can still use two cables to create a so called “wide” port for increased throughput.)
Alex Gerulaitis
Systems Integrator
DV411 – Los Angeles, CA
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